gibbs.h

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/*  This file is part of libDAI - http://www.libdai.org/
 *
 *  Copyright (c) 2006-2011, The libDAI authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
 */




#ifndef __defined_libdai_gibbs_h
#define __defined_libdai_gibbs_h


#include <dai/dai_config.h>
#ifdef DAI_WITH_GIBBS


#include <dai/daialg.h>
#include <dai/factorgraph.h>
#include <dai/properties.h>


namespace dai {



class Gibbs : public DAIAlgFG {
    private:
        typedef std::vector<size_t> _count_t;
        typedef std::vector<size_t> _state_t;
        size_t _sample_count;
        std::vector<_count_t> _var_counts;
        std::vector<_count_t> _factor_counts;
        size_t _iters;
        _state_t _state;
        _state_t _max_state;
        Real _max_score;

    public:
        struct Properties {
            size_t maxiter;

            double maxtime;

            size_t restart;

            size_t burnin;

            size_t verbose;
        } props;

    public:
        Gibbs() : DAIAlgFG(), _sample_count(0), _var_counts(), _factor_counts(), _iters(0), _state(), _max_state(), _max_score(-INFINITY) {}


        Gibbs( const FactorGraph &fg, const PropertySet &opts ) : DAIAlgFG(fg), _sample_count(0), _var_counts(), _factor_counts(), _iters(0), _state(), _max_state(), _max_score(-INFINITY) {
            setProperties( opts );
            construct();
        }



        virtual Gibbs* clone() const { return new Gibbs(*this); }
        virtual Gibbs* construct( const FactorGraph &fg, const PropertySet &opts ) const { return new Gibbs( fg, opts ); }
        virtual std::string name() const { return "GIBBS"; }
        virtual Factor belief( const Var &v ) const { return beliefV( findVar( v ) ); }
        virtual Factor belief( const VarSet &vs ) const;
        virtual Factor beliefV( size_t i ) const;
        virtual Factor beliefF( size_t I ) const;
        virtual std::vector<Factor> beliefs() const;
        virtual Real logZ() const { DAI_THROW(NOT_IMPLEMENTED); return 0.0; }
        std::vector<size_t> findMaximum() const { return _max_state; }
        virtual void init();
        virtual void init( const VarSet &/*ns*/ ) { init(); }
        virtual Real run();
        virtual Real maxDiff() const { DAI_THROW(NOT_IMPLEMENTED); return 0.0; }
        virtual size_t Iterations() const { return _iters; }
        virtual void setMaxIter( size_t maxiter ) { props.maxiter = maxiter; }
        virtual void setProperties( const PropertySet &opts );
        virtual PropertySet getProperties() const;
        virtual std::string printProperties() const;



        void randomizeState();
        std::vector<size_t>& state() { return _state; }
        const std::vector<size_t>& state() const { return _state; }

    private:
        void construct();
        void updateCounts();
        Prob getVarDist( size_t i );
        void resampleVar( size_t i );
        size_t getFactorEntry( size_t I );
        size_t getFactorEntryDiff( size_t I, size_t i );
};



std::vector<size_t> getGibbsState( const FactorGraph &fg, size_t maxiter );


} // end of namespace dai


#endif


#endif